Sealing apparatus for gas compressor

ABSTRACT

Apparatus for sealing the rotor shaft of gas compressor by sealing liquid fed under pressure comprising buffer gas chambers for preventing the leakage of corrosive or noxious gas in the operating gas, non-corrosive and innoxious gas separated from the operating gas by condensation and evaporation being fed into the buffer gas chambers.

Elnited States atent 1 1 m1 339mm Endo et a1. 1 an. 5, 1974 [54] SEALINGAPPARATUS FOR S FOREIGN PATENTS 0R APPLICATIONS COMPRESSOR Inventors:Takamasa Endo; Shojiro Sugimura,

' both of Okayama, Japan Assignee: Mitsui Shipbuilding and Engineering(10., Ltd., Tokyo, Japan Filed: Dec. 8, 1971 Appl. No; 205,879

Foreign Application Priority Data Doc, 16, 1970 Japan 45412108 US. Cl415/175, 415/178, 415/179 int. C1. Fold 11/00, F()4d 29/08 Field ofSearch... 415/175, 176, 177, 178, 179

References Cited UNITED STATES PATENTS 8/1952 Ricc 415/175 1,125,7827/1956 France 415/175 Primary Examiner-Henry F. Raduazo Attorney, Agent,or Firm-Howson and Howson [57] ABSTRACT Apparatus for sealing the rotorshaft of gas compressor by sealing liquid fed under pressure comprisingbuffer gas chambers for preventing the leakage of corrosive or noxiousgas in the operating gas, noncorrosive and innoxious gas separated fromthe operating gas by condensation and evaporation being fed into thebuffer gas chambers.

3 Claims, 2 Drawing Figures I" It; at; I

PATENTEDHAR W I 3.795.460

sum 1 or 2 FIG. 1

SEALING APIARATUS FOR GAS COMPRESSGR This invention relates to a gascompressor using buffer gas, and more particularly to sealing apparatusfor such gas compressor.

The conventional rotary gas compressors are usually provided withequalizing gas chambers, sealing liquid chambers and atmosphericchambers which are arranged in juxtaposition along the axis of the rotorshaft for the purpose of sealing of the rotor shaft. Particularly in thegas compressor where a compressed gas or operating fluid containingcorrosive or noxious gases a buffer gas must be used for preventing ofleakage of the operating fluid. That is, an innoxious buffer gas underpressure is introduced into a buffer gas chamber formed between eachsaid equalizing chamber and rotor, thereby to prevent corrosion ofsealing sleeve in each sealing liquid chamber or danger to the humanbody. Such buffer gas, in prior art, is supplied from the outside, whichmeans that operational cost is increased.

An object of the present invention is to eliminate such disadvantage ofthe conventional apparatus. Generally, saturation temperature of thecorrosive or noxious gas and that of the principal constituent ofoperating fluid are different from each other. Thus, according to thepresent invention, operating fluid is cooled to separate the corrosiveor noxious gases from the main constituent of operating fluid, and thenon-corrosive and innoxious constituent of operating fluid is used asbuffer gas.

The present invention is described hereinafter in detail with referenceto the accompanying drawings, in

which:

FIG. 1 is a schematic illustration ofa gas compressor employing'thesealing apparatus according to the present invention; and

FIG. 2 is a schematic illustration of a gas compressor employing theanother embodiment of the present invention.

Referring now to FIG. 1, there is shown diagrammatically a gas"compressor, generally designated by reference numeral 1, which, as willbe seen, in provided with a rotor 3 enclosed by a casing 2. Each of theshafts 3a, 3b of said rotor 3 is enclosed by a buffer gas chamber 4,equilizing gas chamber 5, sealing liquid chamber 6 and atmosphericchamber 7 which are arranged in side by side relation in that ordertoward the outer end of each shaft as shown, and these chambers arepartitioned from each other with labyrinth packings 8 or partition walls9. In each of said sealing liquid chambers 6, are provided sealingsleeves 10, and sealing liquid is supplied to the chambers 6 through asealing liq uid line 11. Drain pipes 12 and 13 are connected to eachequalizing gas chamber and atmospheric chamber '7, respectively, so thatthe sealing liquid flows into these chambers 5 and 7 is dischargedtherefrom through drain pipes 12 and 13, respectively.

It will be also noted that bleeder pipes 14 and an out let pipe 15 areconnected to the casing 2 of the gas compressor 1, and heat exchangersor gas coolers l6 and 17 are provided in the pipes 14 and 15,respectively. The bottoms of the gas coolers 16 and 17 are connected bypipes to condensate tanks 18 and 19, respectively. The number of the gascoolers 16 and 17 and the condensate tanks 18 and 19 may be suitablyselected in accordance with a desired quantity of buffer gas and otherfactors. An end of a buffer gas pipe line 20 is connected to the topspace in each of the condensate tanks 18 and 19, the other end of thepipe line 20 being connected to the buffer gas chambers 41 of gascompressor 1.

During operation of the gas compressor 1, the operating fluid compressedby the compressor 1 is flown into the gas coolers 16, 17 through bleederpipes 14 or outlet pipe 15, and a part of the operating fluid iscondensed at the gas coolers. The corrosive or noxious gas having highersaturation temperaturethanthat of the main constituent of the operatingfluid is condensed and accumulated in the condensate tanks 18, 19.Therefore, the gas accumulated in the tanks 1% 19 is non-corrosive andinnoxious, and the gas is supplied to the buffer gas chambers 4 throughthe buffer gas pipe line 20. Thus the operating fluid in the gascompressor is perfectly isolated from the chambers 5, 6 and 7. Pressurein the buffer gas chamber 4 is relatively low because pressure in thechamber 21 adjacent thereto on the rotor side is kept at a relativelylow level by means of labyrinth packing or other like means, so thatbuffer gas in the condensate tanks 18, 19 may be introduced directlyinto the buffer gas chamber 4.

Referring now to FllG. 2, there is shown an another embodiment which issuited for the case where the innoxious gases or non-corrosive gasescontained in the operating fluid have easily condensable disposition. InFIG. 2, same reference numerals are used to denote same parts as in thearrangement of FIG. 1, and no explanation is repeated here for theseparts. The differences of this embodiment from that of FIG. 1 are thatan end of the buffer gas pipe line 26 is connected not to the top spacein each of the condensate tanks 18, 19, but to a lower part thereof, andthat an evaporator 22 is incorporated in the line 29.

According to this arrangement, the innoxious or noncorrosive gas in theoperating fluid is reevaporated in the evaporator 22 to utilize it asbuffer gas.

From the foregoing, it will be understood that according to the presentinvention required buffer gas is easily obtained from the apparatusitself without introducing from other buffer gas sources. Also, byenlarging the capacities of the condensate tanks 18, 19, it is possibleto protect the sealing sleeves from damage and the operator from dangerwhen the gascompressor is stopped.

We claim:

1. in a gas compressor apparatus having a rotor mounted on a drivenshaft for compressing an operating fluid, sealing portions at oppositeends of said driven shaft and buffer gas chambers mounted around saidshaft intermediate said rotor and said sealing portions to exclude flowof operating fluid from said rotor into said sealing portions, theimprovement including a heat exchanger for the operating fluid flowingthrough said rotor, means to extract a portion of the operating fluidfrom said heat exchanger including a tank for containing the extractedfluid, said tank comprising means for separating corrosive or noxiouscomponents of the extracted operating fluid from the remainder, andmeans for directing at least a portion of said remainder into saidbuffer gas chambers in gaseous form whereby said buffer gaschambers aresupplied with a gas which is free from corrosive or noxious componentswhich may adversely affect said bearing portions and is composed only ofthe remainder of the operating fluid which does not contaminate saidoperating fluid.

2. Apparatus according to claim 1 wherein said corrosive or noxiouscomponents of said operating fluid have a higher saturation temperaturethan the remainder, said extracting means comprising a conduit connectedto said heat exchanger to direct condensate therefrom into said tank,said tank operating to separate said components by selective evaporationof the condensate, the means for directing at least a portion of saidremainder comprising a conduit having one end connected to the top ofsaid tank and its other end connected into said buffer chambers.

3. Apparatus according to claim 1 wherein said noxbuffer chambers.

1. In a gas compressor apparatus having a rotor mounted on a drivenshaft for compressing an operating fluid, sealing portions at oppositeends of said driven shaft and buffer gas chambers mounted around saidshaft intermediate said rotor and said sealing portions to exclude flowof operating fluid from said rotor into said sealing portions, theimprovement including a heat exchanger for the operating fluid flowingthrough said rotor, means to extract a portion of the operating fluidfrom said heat exchanger including a tank for containing the extractedfluid, said tank comprising means for separating corrosive or noxiouscomponents of the extracted operating fluid from the remainder, andmeans for directing at least a portion of said remainder into saidbuffer gas chambers in gaseous form whereby said buffer gas chambers aresupplied with a gas which is free from corrosive or noxious componentswhich may adversely affect said bearing portions and is composed only ofthe remainder of the operating fluid which does not contaminate saidoperating fluid.
 2. Apparatus according to claim 1 wherein saidcorrosive or noxious components of said operating fluid have a highersaturation temperature than the remainder, said extracting meanscomprising a conduit connected to said heat exchanger to directcondensate therefrom into said tank, said tank operating to separatesaid components by selective evaporation of the condensate, the meansfor directing at least a portion of said remainder comprising a conduithaving one end connected to the top of said tank and its other endconnected into said buffer chambers.
 3. Apparatus according to claim 1wherein said noxious or corrosive components have a lower saturationtemperature than the remainder, said extraction means comprising aconduit connected to collect condensate from said heat exchanger anddirect it into said tank, said means to direct at least a portion ofsaid remainder from said tank comprising a conduit having one endconnected to the bottom of said tank and its other end connected to saidbuffer chambers and an evaporator in said conduit to convert theremainder from condensate form to gaseous form prior to admission intosaid buffer chambers.